Investments (Summary Of Gross Unrealized Gains And Losses And Fair Values) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 143,161	$ 87,151
Available-for-sale Securities, Gross Unrealized Gains	17,619	3,400
Available-for-sale Securities, Gross Unrealized Losses	(114)	(534)
Available-for-sale Securities	160,666	90,017
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	20,610	20,610
Available-for-sale Securities, Gross Unrealized Gains	17,489	3,251
Available-for-sale Securities, Gross Unrealized Losses	0	(367)
Available-for-sale Securities	38,099	23,494
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	122,551	66,541
Available-for-sale Securities, Gross Unrealized Gains	130	149
Available-for-sale Securities, Gross Unrealized Losses	(114)	(167)
Available-for-sale Securities	$ 122,567	$ 66,523